A program linked stereoscopic video service is a service in which a 3D additional image (or file) is transmitted to or stored in a receiver in advance or stored in a separate device, for example, an universal serial but bus (USB) device, or the like, and a reference image is transmitted using an existing digital broadcasting platform, such that the reference image and the 3D additional image stored in the receiver in advance are linked to and synchronized with each other, thereby providing a 3D stereoscopic image.
In Korean Patent Application No. 2010-0005984 (entitled “Method for Processing Non-real time Stereoscopic Services in Terrestrial Digital Multimedia Broadcasting and Apparatus for Receiving Terrestrial Digital Multimedia Broadcasting”), an SS_descriptor is additionally defined in a program map table (PMT) (the SS_descriptor is included in a descriptor loop immediately after a program_info_length in the PMT), and an NRT_marker for signaling a start position (a first frame position) is put in the SS_descriptor in order to synchronize 3D left and right images with each other. That is, a position of a start frame of a 3D broadcasting program is signaled using the SS_descriptor in the PMT.
In this case, a start of the 3D broadcasting program may be identified in a receiver side; however, whether an additional image frame of a 3D real-time broadcasting program starts after 0.5 second, starts after one second, or starts after three seconds based on a reference image of the 3D real-time broadcasting program may not be recognized at all in the receiver side, such that an additional image may not be read from a memory of the receiver in advance for the purpose of preparation.
As resolution of an image becomes high, more contents are stored in the memory of the receiver side, and thus it takes a long time to load and decode the contents stored in the memory.
In Korean Patent Application No. 2010-0005984, in the case in which a plurality of 3D additional images are stored in the receiver, since it is impossible to inform the receiver side of 3D additional image linked information linked to the reference image of the real-time broadcasting program through signaling in advance, the time that is required for the receiver to prepare the 3D additional image linked to the 3D reference image of the real-time broadcasting program in advance may not be provided, such that it takes a long time to load and decode the contents stored in the receiver side memory.